NUMERICAL STUDY OF A HYBRID COUNTERMEASURE FOR RIVER EMBANKMENT IN ACTUAL FIELD CASE

In this study, a hybrid countermeasure for river embankments is proposed consisting of a wall of sheet-piles installed on one side of the toe of embankment and partial floating sheet-piles (PFS) installed on the other. Previous studies show that the PFS method is effective against embankment settlement caused by liquefaction of loose sand and consolidation of soft clay. However, such previous studies were carried out on simple model cases, and hybrid countermeasures on actual embankments have not been thoroughly studied. Therefore, the authors have performed numerical analyses to verify the effectiveness of the hybrid countermeasure applied to actual field conditions with an earthquake motion occurred in the past. It was concluded that the settlement of embankment was reduced by the hybrid countermeasure even in the actual field case. Additionally, authors obtained fundamental data for making a design method, that is the maximum bending stress among the different lengths of the sheet-piles after consolidation.